Spicy Stewed Cauliflower & Potatoes

• 2 potatoes
• 1 onion
• 1 cauliflower
• 1 dry chili (red)
• 60 ml lemon juice
• 60 ml vegetable oil
• 3 gr salt
• 2 gr cayenne
• 1 gr turmeric
• 1 slice green chili